Hierarchical carbon materials with functional groups residing at the surface are prepared for the first time by using nanostructured silica materials as templates in combination with hydrothermal carbonization at mild temperatures (180 degrees C). Different carbon morphologies (e.g., macroporous casts, hollow spheres, carbon nanoparticles, and mesoporous microspheres) can be obtained by simply altering the polarity of the silica surface. The surface functionality and hydrophilicity of the resulting materials are assessed by Fourier transform IR spectroscopy, X-ray photoelectron analysis, and water porosimetry. Raman spectroscopy and X-ray diffraction measurements show that the materials are of the carbon-black type, similar to charcoal.